An animal model for obsessive compulsive disoder: fluoxetine treatment of acral lick dermatitis in dogs

Abstract

Acral Lick Dermatitis (ALD) is a self inflicted skin disorder found in dogs. It is caused by excessive licking of paws and flanks. ALD has been proposed to be an animal model of obsessive compulsive disorder (OCD) in humans. In both conditions, serotonergic neural dysfunction is believed to be responsible for aberrant gooming behaviour. ALD is the first animal model proposed for a psychiatric condition. Serotonergic antidepressants are recommended as first line treatment in OCD and preliminary work has shown ALD sufferers to respond to serotonergic antidepressants. Objective: The aim of the study was to assess the efficacy and tolerability of fluoxetine treatment of ALD in dogs and to investigate ALD as an animal model of the psychiatric condition, OCD. Method: Sixty three dogs with ALD were treated with fluoxetine 20 mg daily, or placebo, for 6 weeks. Results: In the fluoxetine group, owners rated both appearance of the lesion (t = 7.02, df = 29, p < 0.0001) and licking behaviour (t = 10.2, df = 29, p < 0.0001) as significantly improved by the end of the trial. Veterinarian-rated preand post-treatment photographs showed statistically significant improvement in the fluoxetine group alone (mean = 2.55). There were no significant changes in the placebo group as rated by owners and veterinarians. Conclusions: These results demonstrate the efficacy of fluoxetine in the treatment of ALD and lend further support to ALD as an animal model of OCD.